Overview

I am not sure exactly how this Coleman Powermax Adapter came into being at Coleman. On the one hand we have the classic and much-loved Coleman Xtreme stove which takes the Powermax canisters for reliable winter use, and more recently Coleman have released their Fyrestorm Ti stove which takes the ordinary screw-thread canisters and is almost as good in the cold of winter time. The reason for the creation of the Fyrestorm stove is probably because the availability in retail shops of the Powermax canisters has (sadly) never been all that good, although Coleman are committed to keeping them in production, at least for some years to come.

Anyhow, this Adapter fits somewhere in between the two stoves. It allows you to attach a readily-available screw-thread canister to your Xtreme stove, while maintaining the invaluable liquid feed system for winter. In fact it looks vaguely like the canister tripod which comes with the Fyrestorm stove, but its hex 'output' port resembles the hex connector on the Powermax canister. This is illustrated in the second photo, below.

However, I have to report that the Xtreme stove is now out of production - very sadly. It has been replaced in one way by the Coleman Fyrestorm and in another way by the Coleman Xpert stove, which is a slightly heavier four-legged version of the Xtreme. (I predict the eBay price of Xtreme stoves is going to start climbing.) So I am not sure what the market for this Adapter will be. I guess it will be mainly people who love their Xtreme stove and don't want to give it up. However, there is a weight penalty, as illustrated in the table below. The Powermax canister cited is the large one with a 300 g net capacity, and the screw-thread can is the normal 230 g one, so the comparisons are not exact.

Item

grams

ounces

Can g

Can oz

Xtreme stove

312

11.0

86

3.03

Powermax Adapter

100

3.5

Combination

412

14.5

130+

4.6+

Fyrestorm Ti

310

10.9

130+

4.6+

The hex fittings on the canister and the Adapter

As you can see, the Xtreme stove plus Powermax canister is the lightest combination, with the Fyrestorm Ti and a conventional screw-thread canister coming second. Using this adapter to go between an Xtreme and a screw-thread canister is the heaviest combination. However, buying the Powermax Adapter may be a cheaper option than buying a whole new stove.

Does it work as claimed? Certainly. I found that it was easier to attach the Xtreme stove to this Adapter than to a Powermax canister - less of a hard push was required to get them to mate. This is a known problem with some Powermax canisters, especially in the cold, although once you get the knack it is not a problem. Attaching a screw-thread canister to the Adapter is just like attaching an upright stove to a canister.

Problems - maybe

I have found that with some brands of canisters the smooth flow of fuel from an inverted canister can be a problem in warm weather. I believe the problem is with the very smelly additive (sometimes a mercaptan is used) included in small quantities with the butane/propane mix. The idea is that the additive will be quickly smelt when unlit gas escapes. This is a safety feature required by law. However, if the fuel evaporates at the valve rather than at the stove, which it will do if the stove is not cold enough, the additive could remain around the needle valve and could gum up the very fine clearance between the needle valve and its seat, depending on what the additive is. I have had this problem with other stoves (eg an MSR Whisperlite) while experimenting with inverted canisters (of a non-Coleman brand), but I have never had it with a Coleman Powermax canister. For that matter, I have never had this problem with the Coleman Xtreme stove running on a Powermax canister, so the matter is somewhat of a mystery so far. I have checked with Coleman about this, and they have assured me that the additive they use in their brand of fuel canisters will not do this. Obviouisly, they could not comment on other brands.

I have mentioned this here because I did have some flow problems at first with this Adapter. My Xtreme stove would fire up and then die - several times. I gave the Adapter tripod plus attached canister a shake and wiggled the stove control valve open and shut a couple of times, and even allowed a little liquid fuel to flush through the hex connector on the Adapter (outside!). This connector has a shut-off valve inside it, just the same as the Lindal valve on the canister. After doing this the combination of Adapter and stove seemed to work correctly. Coleman tell me they have had a few (not many) reports of this sort of problem and they suspect that something may have gummed up the shut-off valve on the Adapter connector somehow. This tallies with the fact that once I had really flushed the system out, it seemed to work just fine thereafter.

After clearing the problem I fired up the system, checked the fuel line between the Xtreme valve (with the big black knob) and the stove, and found it was now cold. This suggested that the place of evaporation had moved down the line from the shut-off valve on the Adapter, through the Xtreme valve, and towards the stove. This is how it shgould be in cold weather, and thereafter the stove ran smoothly.

Summary

This Coleman Powermax Adapter does work to allow you to use an Xtreme stove with a common screw-thread canister in winter time for fairly little cost. That said, if you are looking for a serious winter canister stove and can only get the screw-thread canisters, I think I would recommend you consider biting the bullet and buying a new Fyrestorm instead: it will be lighter.